What happens if you remove the mirror from the DSLR and use https://www.artlook.us/service/wedding-proposal-photography/? The dimensions will decrease, the viewfinder will become electronic (if necessary), autofocus will work according to the contrast method and, possibly, the reliability of the camera will increase (we remove the moving element – the mirror). Historically, a mirror has been necessary for sighting and the operation of the phase
autofocus method, but progress does not stand still. The appearance of “fast” matrices (reading speed of 240 frames per second), powerful processors and high-quality electronic viewfinders made it possible to create cameras that are almost in no way inferior to DSLRs. Large sensors, including full-frame ones, advanced functionality that SLR cameras cannot boast of – all this allows mirrorless cameras to conquer an increasing percentage of the digital camera market every year. Everyone will be able to choose a mirrorless camera to their liking.
Conventionally, all mirrorless cameras can be divided into 3 categories:
amateur entry-level;
amateur middle level;
semi-professional.
By the way, system cameras, mirrorless cameras, cameras with interchangeable lenses – all these are the names of these cameras.
Mirrorless systems are the youngest on the market. 
The first mirrorless system standard was introduced in 2008 by Olympus and Panasonic and was called micro4/3. Olympus and Panasonic produce cameras and lenses of the same standard, you can safely put Panasonic lenses on Olympus cameras, and vice versa. All other manufacturers promote their own standards. Accordingly, the fleet of optics from different manufacturers can vary greatly. The micro4/3 system has the largest selection of lenses (both Olympus and Panasonic have large lines of optics), other manufacturers also have enough lenses for all occasions. On some systems, you can put lenses from SLR cameras through an adapter with autofocus support, but, as a rule, nothing good will come of this – the camera size increases significantly, and the autofocus speed of such a bundle leaves much to be desired.
When choosing a camera, just like with SLR cameras, you need to pay attention to the package. One and the same camera can be sold in options:
Body (only “carcass”);
Kit (with one lens);
DoubleKit (with two lenses).